National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

Radiant Heating of Mine Bulkheads.

PB300363

Publication Date	1979
Personal Author	Edwards, J. C.
Page Count	21
Abstract	The Bureau of Mines has developed a time-dependent mathematical model of radiative heating of bulkheads in mines. The model includes both reradiation from the duct (cylindrical) walls and direct radiation from the fire zone. Thermal loss into the wall of the duct and into the bulkhead is included. Both brick and wood bulkheads are considered. It is found that the heating rate of the system scales as the duct length-to-diameter ratio and the flame temperature. In particular, the time required for the irradiated surface of the bulkhead to reach a specified temperature decreases with increasing flame temperature for a fixed length-to-diameter ratio and increases with increasing length-to-diameter ratio for a specified flame temperature. It is also determined that the time, tau, for the bulkhead surface temperature to reach a specific value, T sub b, for a fixed length-to-diameter ratio less than 4 and for a flame temperature of 1,200 K is approximately linearly dependent on T sub b for 500 K < T sub b < 700 K, and is nearly exponentially dependent on the length-to-diameter ratio for T sub b = 600 and 700 K.
Keywords	Radiant heating Fire safety Bulkheads Mathematical models Mines(Excavations) Coal mines Mine safety
Source Agency	Bureau of Mines
NTIS Subject Category	48A - Mineral Industries
Corporate Authors	Bureau of Mines, Pittsburgh, PA. Pittsburgh Mining and Safety Research Center.
Document Type	Technical Report
NTIS Issue Number	197926

Radiant Heating of Mine Bulkheads.

Radiant Heating of Mine Bulkheads.
PB300363

Publication Date	1979
Personal Author	Edwards, J. C.
Page Count	21
Abstract	The Bureau of Mines has developed a time-dependent mathematical model of radiative heating of bulkheads in mines. The model includes both reradiation from the duct (cylindrical) walls and direct radiation from the fire zone. Thermal loss into the wall of the duct and into the bulkhead is included. Both brick and wood bulkheads are considered. It is found that the heating rate of the system scales as the duct length-to-diameter ratio and the flame temperature. In particular, the time required for the irradiated surface of the bulkhead to reach a specified temperature decreases with increasing flame temperature for a fixed length-to-diameter ratio and increases with increasing length-to-diameter ratio for a specified flame temperature. It is also determined that the time, tau, for the bulkhead surface temperature to reach a specific value, T sub b, for a fixed length-to-diameter ratio less than 4 and for a flame temperature of 1,200 K is approximately linearly dependent on T sub b for 500 K < T sub b < 700 K, and is nearly exponentially dependent on the length-to-diameter ratio for T sub b = 600 and 700 K.
Keywords	Radiant heating Fire safety Bulkheads Mathematical models Mines(Excavations) Coal mines Mine safety
Source Agency	Bureau of Mines
NTIS Subject Category	48A - Mineral Industries
Corporate Authors	Bureau of Mines, Pittsburgh, PA. Pittsburgh Mining and Safety Research Center.
Document Type	Technical Report
NTIS Issue Number	197926